Ink-jet printers generally use inks that contain water-soluble dyes. Such dyes are often not very smear resistant or water resistant when printed on paper.
The use of colored inks in ink-jet printing is known; for example, U.S. Pat. No. 4,382,262 and U.S. Pat. No. 4,360,548 disclose such systems. These patents, however, do not disclose or suggest forming smear-resistant inks on a substrate, such as paper.
Hackleman and Pawlowski addressed this problem in U.S. Pat. No. 4,694,302. In their method, a polymer is formed on the substrate from two reactive components; one component may be in the ink and the other may be in the substrate or it may be applied from a second reservoir. The resultant polymer binds the dye. In one example, sebacyl chloride was include in the ink; when it was deposited on a cellulose-containing substrate, it formed a cellulosic polymer. In another example, the ink contained carboxymethyl cellulose, and a second solution contained 2% AlCl.sub.3. When these solutions were deposited on a substrate, they reacted to form an insoluble salt of the carboxymethyl cellulose polymer.
A method for determining the degree of reactive dye bonding to cellulose is summarized in Dialogue abstract 268024 50-08024. Dyed chromatographic paper is boiled for 5 minutes in distilled water followed by colorimetric determination of the desorbed dye. The summary also notes that the test can be used for the determination of the effects of alkali concentration on the bonding degree.